Solar cells, also termed photovoltaic or PV cells, convert sunlight into electricity. Traditionally, these electronic devices have been fabricated using silicon (Si) as a light-absorbing, semiconducting material in a relatively expensive production process. To make solar cells more economically viable, solar cell device architectures have recently been developed that use thin-film, light-absorbing semiconductor materials such as copper-indium-gallium-sulfo-di-selenide, also termed CIGS.
Despite the demonstrated potential of CIGS in thin-film solar cells, the toxicity and low abundance of indium and selenium are major impediments to the widespread use and acceptance of CIGS in commercial devices. Attractive alternatives to CIGS include quaternary chalcogenides, particularly copper zinc tin sulfide, Cu2ZnSnS4 (CZTS). It has a bandgap of about 1.5 eV, well within the solar spectrum, and an absorption coefficient greater than 104 cm−1. In addition, the CZTS elements are non-toxic and abundant.
CTZS has been produced from solution using ultrasonic or microwave initiation. In some instances, additional additives have been employed in processes to produce the chalcogenide analogs. CZTS has also been produced by vapor deposition techniques.
There remains a need for a robust process to produce CZTS at a commercial scale.